1. Technical Field
The present invention relates generally to an apparatus and method for detecting signals and, more particularly, to an apparatus and method for detecting signals that process a received wired or wireless signal in accordance with a predetermined condition so that the characteristics of the signal and information about the arrival direction, location, and type of the signal can be determined.
2. Description of the Related Art
With the development of information and communication technology, information based on information and communication technology is frequently transferred and obtained in private, government, or military organizations. Furthermore, the demand for the blocking of information and communication technology equipment used for obtaining such information is also increasing in response thereto.
In particular, these days, persons or anti-governmental organizations often attempt to collect or attack specific information using illegal equipment. This leads to the divulgence of information, and may damage a physically established public infrastructure. If a signal is distorted or a disrupting signal is generated in a smart grid, a public transportation network or an information collection detector, serious physical damage may occur, or there may arise a problem that adversely impacts upon the normal functioning of society. In general, a signal detector is used as a piece of equipment for efficiently detecting and tracking such an abnormal signal.
Technology for a signal detector basically includes a signal detection technique capable of determining whether a signal is present, an analysis technique capable of determining whether a signal is illegal, and a direction detection technique capable of estimating the location of a signal. In general, in the signal detection technique, a signal is detected when the output of the signal is higher than a specific signal level in the frequency domain. The simplest method of determining whether the detected signal is an illegal signal is to determine whether the detected signal is used at a permitted frequency in a permitted signal form. In another method, a user checks all signals, prepares a list of the signals, maintains the list, and determines that a signal not included in the list is an abnormal signal when the signal not included in the list is generated during a future operation.
Furthermore, a directional antenna is commonly used to track the location of a signal source related to a detected abnormal signal. The directional antenna displays the intensity of a signal, or converts the signal into sound that can be heard by a user and outputs the converted signal, and the user detects a signal source using a direction detection antenna. In order to precisely detect the direction of a signal, a method of deploying an antenna in a remote place, unlike a method using a portable direction detection antenna, analyzing the magnitude and phase of a signal received at each location using the antenna, and estimating the direction and location of the signal based on the magnitude and phase has also been developed.
Various types of conventional signal detection equipment do not include a function for analyzing a signal itself in a detailed manner, and thus require a user to perform various tasks. For example, when the conventional signal detection equipment analyzes the characteristics of a detected signal and notifies a user of the type of transmitter that sent the detected signal and the place from which the detected signal was sent, the user has to perform various tasks (i.e., estimating a signal modulation scheme, estimating a communication protocol, decrypting a digital password, and detecting a direction) or collect or classify information based on an external special device. In this approach, signals have to be allowed until a user finishes analyzing a specific signal, and it takes a long time to take countermeasures.
As a conventional art, U.S. Pat. No. 8,175,539 discloses a system and method for managing a shared frequency band. The technology disclosed in U.S. Pat. No. 8,175,539 relates to a method of performing communication while minimizing mutual interference in a sharing band. In other words, in the technology disclosed in U.S. Pat. No. 8,175,539, in order to minimize interference in a sharing band, each communication entity continuously monitors a channel, and performs communication using another channel or method if a signal that may collide with its own signal is detected.
The technology disclosed in U.S. Pat. No. 8,175,539 does not have a solution to an unknown signal because a signal is determined based on only some analog information. Furthermore, in the technology disclosed in U.S. Pat. No. 8,175,539, a signal is not detected, but rather an interference signal is avoided. To this end, the main objective of the technology disclosed in U.S. Pat. No. 8,175,539 is to classify signals in order to select a band through which an interference signal can be avoided when the interference signal is detected.
As another conventional art, U.S. Pat. No. 8,050,413 discloses a system and method for conditioning a signal received at an MEMS-based acquisition device. The technology disclosed in U.S. Pat. No. 8,050,413 relates to the detection of events for an unmanned security sensor. In a method of recording and observing an environment in a security system, information about the environment has to be obtained in order to record the environment and detect an intrusion efficiently, because a high memory capacity is required to record the environments continuously. To this end, the technology disclosed in U.S. Pat. No. 8,050,413 proposes the detection of signals corresponding to a sound band and a visible ray band in order to obtain environment information. If energy is detected in one or more bands when a sound band is detected, it is determined that an event has occurred. If light that is higher than a specific luminous intensity is detected in the corresponding environment, it is determined that an event has occurred. When this event occurs, the security sensor performs the operation of recording images and video of a surrounding environment at the same time. A detection band is extended in order to effectively ensure an event, and a bandwidth of 100 KHz or higher that is much higher than the audible range is observed using an MEMS-based sensor in order to extend the detection band. The characteristics of a signal detected in this bandwidth are classified based on frequency bands, and an event is generated based on the classified characteristics.
In the technology disclosed in U.S. Pat. No. 8,050,413, the security sensor capable of detecting a sound and light is configured and mounted in an MEMS form. Furthermore, when a sound or light is detected, a band in which a sound or light has been detected is determined and, a security detector is operated. Whether an event is present is determined based on whether a sound or light is present.